Structure for an optical switch on a substrate

• US 6,504,643 B1
• Filed: 09/28/2000
• Issued: 01/07/2003
• Est. Priority Date: 09/28/2000
• Status: Expired due to Term

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Fork, David K., Peeters, Eric, Rosa, Michel A.
• Primary Examiner(s): Lester, Evelyn A.
• Application Number:
  US09/675,045
• Time in Patent Office: 831 Days
• Field of Search: 359/290, 359/291, 359/298, 359/224, 257/415, 257/417-420
• US Class Current: 359/290
• CPC Class Codes: B81B 2201/045 Optical switches
• CPC Class Codes: B81B 3/0021 Transducers for transforming electrical into mechanical energy or vice versa dynamo-electric machines H02K99/00; electrostatic machines H02N1/00; piezoelectric devices H10N30/00
• CPC Class Codes: B81B 7/0003 MEMS mechanisms for assembling automatically hinged components, self-assembly devices self-assembly processes B81C1/00007
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G02B 6/3518 the reflective optical element being an intrinsic part of a MEMS device, i.e. fabricated together with the MEMS device MEMS devices in general B81B; manufacture of MEM devices in general B81C; micromechanical devices controlling the direction of light G02B26/0833
• CPC Class Codes: G02B 6/3556 NxM switch, i.e. regular arrays of switches elements of matrix type constellation
• CPC Class Codes: G02B 6/358 Latching of the moving element, i.e. maintaining or holding the moving element in place once operation has been performed; includes a mechanically bistable system
• CPC Class Codes: G02B 6/3584 constructional details of an associated actuator having a MEMS construction, i.e. constructed using semiconductor technology such as etching MEMS per se B81B, B81C
• CPC Class Codes: Y10S 359/904 Micromirror

Abstract

Optical cross-connect involve the general concept of a two dimensional array of MEMS tilt mirrors being used to direct light coming from a first optical fiber to a second optical fiber. Each MEMS tilt mirror in the two dimensional array can rotate about its x and y axis and is suspended by a plurality of suspension arms attached to a substrate.

Claims

1. An actuatable mirror structure comprising:

a substrate;

a plurality of suspension arms each comprising an internal stress gradient layer, each said plurality of suspension arms having a first end and a second end, said first end being attached to said substrate;

a polysilicon area having a reflective surface layer, said polysilicon area being attached to said second end of said plurality of suspension arms;

and

a plurality of electrodes arranged on said substrate adjacent to said plurality of suspension arms to create an electric field for producing deflective movement of said polysilicon area having said reflective surface layer.

2. The structure of claim 1 wherein said plurality of suspension arms is three in number.

3. The structure of claim 1 wherein said substrate is glass.

4. The structure of claim 1 wherein said internal stress gradient layer comprises MoCr.

5. The structure of claim 4 wherein an internal stress gradient is on the order of 3 gigapascal across said stress gradient layer.

6. The structure of claim 1 wherein said polysilicon area has a substantially square shape.

7. The structure of claim 1 wherein said polysilicon area is comprised of two polysilicon layers having internal stress gradients acting in opposite directions.

8. The actuatable mirror structure of claim 1 wherein each of said plurality of electrodes has a substantially tapered shape.

9. An array of actuatable mirror structures, wherein each of said actuatable mirror structures comprises a structure in accordance with claim 1.

10. The structure claim 9 wherein said array is a two dimensional rectilinear array.

11. The structure of claim 1 wherein each of said plurality of electrodes extends underneath said metal area.

12. An actuatable mirror structure comprising:

a substrate;

four suspension arms each comprising an internal stress gradient polysilicon layer, each said suspension arm having a first end and a second end, said first end being attached to said substrate;

a polysilicon area having a reflective surface layer, said polysilicon area being attached to said second end of each of said four suspension arms; and

four electrodes arranged on said glass substrate adjacent to said four metal suspension arms, respectively, to create an electric field for producing deflective movement of said polysilicon area having said reflective surface layer.

13. An array of actuatable mirror structures, wherein each of said actuatable mirror structures comprises a structure in accordance with claim 12.

14. The array of claim 13 wherein said array is a two dimensional rectilinear array.